Talk:Centriole

Quote
In 1996 Dr Stuart Black and associates at the University of Chester discovered in a longitudinal study that children suffering stunted growth suffered from greatly reduced rates of cell mitosis, this also affected their ability to kill as quickly when compared to a control sample of those of average height. This is believed to be significant in showing that their centrioles had greater difficulty initiating the mitosis process due to the third spindle only consisting of two microtubules, instead of three.

I deleted this from the main article. There's no reference to the study in the article and i couldn't find itin a quick pub med search. It's also not written well- what, the shorter children couldn't kill as quicly as their taller counterparts? I doubt that. Amutepiggy 23:08, 9 November 2006 (UTC)

Centrioles are structurally identical to the basal body

I thought it was the centrosome that the basal body was identical to, not the centrioles. I'm not certain enough to change it though. Anyone know? 80.42.108.167 10:40, 9 April 2006 (UTC)

Unless you go into more detail about the processes (including the biogenesis of cilia and flagellum)that form the basal body and spindle apparatus, I'd leave it as it is for now. In eukaryotes, most authors refer to the basal body as being similar(homologous)to the centriole. The centrosome refers to the central microtubule organizing center (MTOC) that the nine double or triplet microtubules grow out of to make up the centriole. In cilia and flagellum there are then two more microtubules in the middle of the centriole that form the basal body that the cilia or flagellum grow out of. The centriole forms the spindle for mitosis or the basal body for cilia and flagellum, but not all basal bodies are the same and they undergo a flagellar modification in different species, e.g., the flagellar hook-basal body complex with the protein FliE. Also, dyneins then move back down the centrosome microtubules to transport ATP toward the centrosome (MTOC).

In Dr. Jim Deacon, of the University of Edinburgh, Genetic's Glossary: "The centriole is a short cylindrical organelle, found in pairs arranged at right angles to each other at the centre of a microtubule organizing centre (MTOC) or centrosome, found in eukaryotes (except in higher plants). A centriole is similar in structure to the basal body found at the base of eukaryotic cilia and flagella and organises the axoneme, the bundle of microtubules and other proteins forming the core of each cilium or flagellum. The centrosome organizes formation of a spindle during mitosis or meiosis." http://helios.bto.ed.ac.uk/bto/glossary/c.htm

"[During the G1 and S phase of mitosis in mammalian cells] An older centriole differs functionally from a younger centriole by being able to assemble a primary cilium. This suggests a role for one or more of these proteins and for maturation in promoting the assembly of the cilium. Of those, only -tubulin has been identified to date in Chlamydomonas. In addition to the presence of the above proteins, the level of polyglutamylation on - and ß-tubulin is increased on older centrioles and on older basal bodies. Unlike centrioles, daughter basal bodies must mature early in their first cell cycle in order to assemble flagella or cilia and so for example, all basal bodies in the ciliated epithelium of the trachea have the ODF2 epitope (McKean et al., 2003). Therefore, there is a need for an additional maturation event in basal bodies which we refer to as early maturation and which must occur at M/G1 phase of the cell cycle rather than in G2/M phase, as for centrioles." From: "Mutations in -tubulin promote basal body maturation and flagellar assembly in the absence of -tubulin," by Sylvia Fromherz, Thomas H. Giddings, Jr, Natalia Gomez-Ospina1, and Susan K. Dutcher. Journal of Cell Science 117, 303-314 (2004). Published online at http://jcs.biologists.org/cgi/content/full/117/2/303

"In a confluent culture [of Chlamydomonas], Fa2p is observed lying on the presumptive ciliary SOFA and at the base of both centrioles, one of which is serving as the basal body. During mitosis, Fa2p is associated with the duplicated centrioles and then with the polar region of the mitotic spindle in the mouse cells, as it is in Chlamydomonas.” From: “Cilia and the cell cycle?” by Lynne M. Quarmby and Jeremy D.K. Parker, JCB, Volume 169, Number 5, 707-710. Published online at http://www.jcb.org/cgi/content/full/169/5/707

What they do
"A basal body (also called a basal granule or kinetosome) is an organelle formed from a centriole, and a short cylindrical array of microtubules. It is found at the base of a eukaryotic undulipodium (cilium or flagellum) and serves as a nucleation site for the growth of the axoneme microtubules. Centrioles, from which basal bodies are derived, act as anchoring sites for proteins that in turn anchor microtubules within centrosomes, one type of microtubule organizing center (MTOC). These microtubules provide structure and facilitate movement of vesicles and organelles within many eukaryotic cells. Basal bodies, however, are specifically the bases for cilia and flagella that extend out of the cell." -http://en.wikipedia.org/wiki/Basal_body

The problem is people mixing up the functions of centrosomes, centrioles and basal bodies. It is possible that the centriole's primary, or even only function, is in the formation of basal bodies in order to produce cilia and flagella. Centroiles evolved in single celled eukaryotes, probably aiding in motility - they form flagella. The mitotic spindle then evolved as a means of segregating centrioles and making sure each daughter cell had a flagellum. So instead of centrioles being important for the formation of the spindle, it is possible that the spindle is instead important for the segregation of centrioles. There are eukaryotes that lack cilia or flagella and it should be noted that these taxa also lack centrioles, yet are still perfectly capable of dividing and forming microtubles. These linages probably lost their centrioles as opposed to having never possessed them. Mitosis may have evolved primarily for the segregation of centrioles, but has since taken on other functions including cell division and chromosome segregation. Such critical functions would suggests why the loss of centrioles has not resulted in the loss of mitosis, in spite of it having originally evolved as a mechanisms for centriole segregation.

What people seem to forget when they look at centrioles is how important cilia and flagella are to organisms that process them. If centrioles exist purely for their role in the formation of cilia and flagella, this would be more than enough to explain their existence and evolutionary conservation. Any single celled organism with defects in its flagella or cilia, or metazoan with defects in its primary cilia, motile cilia or flagella, will not survive. The functions of these organelles are critical and therefore the centriole is critical in all organisms that possess these structures.

—Preceding unsigned comment added by SlashRageQuit (talk • contribs) 04:48, 25 June 2010 (UTC)

Animal Development

 * "Proper orientation of cilia via centriole positioning toward the posterior of embryonic node cells is critical for establishing left–right asymmetry during mammalian development.(citation needed)"

Would think this is rather significant, either it can be referenced or should be deleted. --70.128.124.199 (talk) 01:33, 20 October 2010 (UTC)

Do the mother centriole and daughter centriole separate and when?
This article is very confusing when it comes to how the centrosomes/centrioles duplicate. Can someone clarify? —Kelvinsong (talk) 02:13, 10 December 2012 (UTC)

Assessment comment
Substituted at 11:10, 29 April 2016 (UTC)

Cell development and mutant flies
I believe the discussion of "mutant flies" in Centriole could be better integrated with the rest of the paragraph. It seems to be a bit out-of-place. Somerandomuser (talk) 20:35, 12 May 2017 (UTC)

Main diagram simplification
I believe this article's main diagram adds unnecessary complexity through the use of numbered labels. Would it be a good idea to add the labels into the diagram? Somerandomuser (talk) 20:46, 12 May 2017 (UTC)